I'm not sure how you can retire from something you've never done, so I think her description is inaccurate.
Essentially she is not in employment or intending to be in the future. How she/her partner funds this is their business.
That said I'm not sure I could get that worked up about it. If that's how she wants to frame it, well fine.
If I met someone who said they were retired and I asked what they did previously (chit chat) and they said "housewife" I'd internally find the description a bit odd, but wouldn't show it.
Truth is her situation is becoming increasingly less common. Not many women are in a position to be full time SAHM's for extended periods that morph into a life of being voluntarily unemployed.
I know someone in a similar situation and wouldn't swap. I enjoy my work and the financial freedom it has given me. I will in the future enjoy my pension (that I've spent years maxing out) safe in the knowledge I will be fine, even if my DH turned out to be an utter shit (highly unlikely, but I wouldn't be the first).
I've enjoyed being a role model to my children in doing well in my career which has helped fuel their aspirations and frankly provided a lifestyle way beyond us being a single income family could have attained (despite DH also having a very good career).
So, essentially each to their own. Let her describe herself as she pleases, but in honesty yes, she hasn't retired. She is just continuing to be in a position to choose not to work.